But this year, there were moments when they didn't know if they would all get out alive.

"It's a good day for us because we don’t get to see each other. So it's a big event for us," said Bob Morley, one of six first responders who spoke publicly for the first time about their experience during the bombings.

Collectively they have well over 100 years experience on duty at Boston Marathons. One of the first memories they all share is the happiness of the day at 2:48 p.m. and the thought of the main pack of runners arriving at the finish line with various sports injuries.

One minute later the first explosion happened a few feet from the finish line.

"After the first blast, you could feel it. After the second, you knew it was something bad," said EMT Miguel Diaz.

"It was just a matter of seconds before we started getting updates on the radio that we did have devices explode," said EMT Walter Dunbar.

EMS trains for terror attacks prior to events as big as the Boston Marathon. The finish line area has more than 1,700 medical volunteers in addition 103 uniformed first responders on site.

"This was the perfect storm for us," said Captain Bob Haley about all the resources available close to the victims. "It was almost an assembly line as they came through the medical tent."

EMTs not assigned to the tent went directly to victims on Boylston Street.

"We went to where the sound was," said Joanne Dance.

They all remember a calmness amidst the chaos they had not experienced at an emergency scene so large. The volume of patients was new, too, with even critically injured amputees alert and communicating.

"When I was coming down people were just running toward me," said Special Operations paramedic Rafael Hernandez. "When I got to Exeter and Boylston (streets), I found people laid out with amputated legs and arms."

None of them could be sure a third bomb wouldn't detonate. In fact, they mentally prepared for it.

"Of course it was on everyone’s mind," said Morley. "Anyone who’s had training knew that there was the potential of something bad."

"I think the hardest part was just not knowing if we’d all go home safe that night," said EMT Walter Dunbar. "And just knowing the struggle ahead of those victims."

EMS tagged priority victims as they arrived in wheelchairs and stretchers at the main medical tent at Dartmouth Street and Boylston. Ninety two people were transported to area hospitals within 30 minutes of the explosions.

"There were wounds that were just all over the place," Morley said. "Anywhere on your body you can imagine."

"I had some victims that were just pointing at their ears. After a while you realize, you know what, they can’t hear you," Diaz said.

"I can remember some of the victims saying, 'Take that one. I’m OK,' or saying, 'This one’s worse than me,' and they were in no better shape, believe me," Hernandez said.

Every patient that left in an ambulance alive survived the blasts. EMS gives much of the credit to the medical volunteers and strangers who jumped in to help even if it meant being trained on using a tourniquet in the middle of chaos.

"Show of hands: How many of you plan on working at next year's marathon?" NewsCenter 5's Sean Kelly asked.